Getting a map marker by its ID in Google Maps v2

Question

basically when adding a marker to the map it returns the new marker and you can gets the marker id from it like so

Marker m = map.addMarker(new MarkerOptions()
                            .position(new LatLng(lat,lon)));
String id = m.getId();

is there a way to get a marker by its id if there are many markers and you just want to delete one?

Hiren Patel · Answer 1 · 2015-11-23T04:47:52.323

39

I have done this way:

Initialize variables:

private GoogleMap mMap;
private HashMap<Marker, Integer> mHashMap = new HashMap<Marker, Integer>();
private ArrayList<MyCustomModelClass> myList = new ArrayList<MyCustomModelClass>();

Add marker on google map using your arraylist:

for (int i = 0; i < myList.size(); i++) {
    double latitude = myList.getLatitude();
    double longitude = myList.getLongitude();
    Marker marker = mMap.addMarker(new MarkerOptions().position(new LatLng(latitude,longitude))).title(myList.getTitle())
                                        .icon(BitmapDescriptorFactory.fromResource(R.drawable.location_icon));
    mHashMap.put(marker, i);
}

On marker click listener:

@Override
public boolean onMarkerClick(Marker marker) { 
    int pos = mHashMap.get(marker);
    Log.i("Position of arraylist", pos+"");
}

Hope this will help you.

edited Nov 23 '15 at 04:47

answered Apr 22 '15 at 11:25

Hiren Patel

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3

Great answer. This is the way to go. – ADL Nov 22 '15 at 07:58
@ADL, Glad to help you. :) – Hiren Patel Nov 23 '15 at 04:47
5

Very bad idea to use Marker as the key. – zyamys Feb 08 '17 at 20:16
1

Really helpful. You apparently saved me a two to three day stress @HirenPatel – XY-JOE Mar 07 '18 at 22:05
Thank you has been useful to me, in kotlin changing `` for ` ` I was able to add a url (string) to the marker and then use it when clicking on infowindows : `private val mHashMap = HashMap()` – Mario Burga Jun 29 '18 at 21:58

score 22 · Accepted Answer · answered Mar 12 '13 at 18:22

The problem is that the marker id is generated automaticlly and cannot be used for tracking the markers individually. A number of strategies have been proposed work around this. One would be to use a hash map to track markers and then use a key you choose to find a speific marker and remove it. Another idea is to overload one of the marker fields, like snippet, and then add a key yourself. For example, if you were making a new marker (using the google example code) you could put your own key string into the snippet field

mMap.addMarker(new MarkerOptions()                           
.position(MELBOURNE)                           
.title("Melbourne")                           
.snippet(KEY + "Population: 4,137,400"));

Later you could retrive that key using

String s = marker.getSnippet()
String key = s.substring(start, end)

and then use a conditional to remove a specific marker if it is a match. Depending on whatyou need to do one approach my be easier and more efficient than another.

score 13 · Answer 3 · answered Sep 06 '18 at 06:17

13

I know, its very late. But now, we can directly add a unique TAG to a marker.

Marker marker = mMap.addMarker(markerOptions);
marker.setTag("");

Google Developers link about map marker TAG

answered Sep 06 '18 at 06:17

Ashish John

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is it better to use setTag or to use a hashmap? – speedox Jan 26 '20 at 20:09
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Definitely better, you can store any Object into a tag. – netpork Jun 18 '20 at 10:51
This is the right solution, and @netpork thanks for the suggestion, I have missed the Tag documentation about passing Object. – Viktor Jovanovski Mar 20 '21 at 13:42

score 4 · Answer 4 · answered Feb 12 '16 at 13:07

Use WeakHashMap<Integer,Marker> to store markers because in this way, we wouldn't keep a reference to a Marker in memory, and wouldn't have to worry about garbage collected markers.

secondly recommended way to do this is to have a WeakHashMap with ID and your custom data. The documentation says that marker object may change, so don't use the marker as the key. if the activity is killed and restored but the ID will remain the same. sometime it may return null also if marker objects changed.

WeakHashMap<Integer,Marker> obj = new WeakHashMap <Integer,Marker>();

Hope it will help future viewers...

Thanks for the alert :) – karthik kolanji Aug 25 '16 at 07:11 — karthik kolanji, Aug 25 '16 at 07:11

score 0 · Answer 5 · edited Nov 17 '14 at 11:01

0

The best way to do this is using a Map <int, Mark> dictionaryMark;.

Just add the mark into your dictionary each time you draw it.

edited Nov 17 '14 at 11:01

fejese

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answered Nov 17 '14 at 09:43

AbelMorgan

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Getting a map marker by its ID in Google Maps v2

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